The world will eventually move to a low-carbon economy, but it may be too late to avoid the worst effects of climate change, according to John Kerry.

Speaking at the World Economic Forum in Davos, Switzerland, on Tuesday morning, the U.S. special presidential envoy for climate issued a stark warning about the years ahead.

“I’m convinced we will get to a low-carbon, no-carbon economy — we’re going to get there because we have to,” he said.

“I am not convinced we’re going to get there in time to do what the scientists said, which is avoid the worst consequences of the crisis,” he added.

“And those worst consequences are going to affect millions of people all around the world, [in] Africa and other places. Of the 20 most affected countries in the world from [the] climate crisis, 17 are in Africa.”

In his remarks, Kerry also spoke about the task of keeping the goal of limiting global warming to 1.5 degrees Celsius alive.

“So, how do we get there? Well, the lesson I’ve learned in the last years and I learned it as secretary [of State] and I’ve learned it since, reinforced in spades, is: money, money, money, money, money, money, money. And I’m sorry to say that.”

The 1.5 degrees goal is contained within 2015′s Paris Agreement, an accord that aims to “limit global warming to well below 2, preferably to 1.5 degrees Celsius, compared to pre-industrial levels.”

Cutting human-made carbon dioxide emissions to net-zero by 2050 is seen as crucial when it comes to meeting the 1.5 degrees Celsius target.

Over the past few years, many multinational corporations have announced net-zero pledges.

While such commitments draw attention, actually achieving them is a huge task with significant financial and logistical hurdles. The devil is in the detail and goals can often be light on the latter.

Kerry addressed the topic in his speech. “Let’s face it, [a] whole bunch of companies in the world have chosen to say, ‘I’m going to be net zero by 2050’,” he said.

“And you and I, we know they don’t have a clue how they’re going to get there. And most of them are not on track to get there.”